Hydroxamic acids of formula I
wherein R1 and R2 are independently hydrogen, C1-6 alkyl, or —CCH; R3 and R4 are independently hydrogen or C1-6 alkyl; and R5 is H, —C(O)—C1-6 alkyl, —C(O)—C3-6 cycloalkyl, —C(O)-aryl, —C(O)-heteroaryl, —C(O)O—C1-6 alkyl, —C(O)O-aryl, or silyl, are inhibitors of TNF-a converting enzyme (TACE) suggesting their potential utilities in the treatment of disease conditions such as rheumatoid arthritis and osteoarthritis (see U.S. Pat. No. 6,225,311 B1, the entire disclosure of which is incorporated by reference herein). Enantiomers can display different TACE-binding activities, and their selectivity and metabolic effects may be different. An efficient, inexpensive and scaleable process for preparing the optically preferred hydroxamic acids is desirable.